Breakpoints are not hit in silverlight

Question

I tried a simple web application using WCF as web service and web clilent is developing using silverlight sdk.4. But there's a problem when loading data to web page. Then I wanted to debug  the application. Though I set break points in the code behind it directly goes to the web page without going through break points.Seems that it break points aren't hit.

Can anyone has this kind of experience? Please help me to resolve this problem